From patchwork Mon Nov 9 12:55:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 322796 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC428C2D0A3 for ; Mon, 9 Nov 2020 13:04:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C756208FE for ; Mon, 9 Nov 2020 13:04:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927090; bh=jP88JYj8Z/AdPCNX+iDECNYYOP9MgaPxV5cN5R2kP8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=GSuPjIuH6vjydyDTdOcqB3wUyUdVemSq1KV6FNpl35DZ3TrKR5NxozWr3ZVzDOzdD TL67TrZwA4LAtQnM43qAXdwUy6jpXjw/HcCjUL8zV8ce/1h/b54SACZdEzZKawDvEK dyVEq1SguzG+yWHeQSIS5v1w+IaxerHC/Isi3TC4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730490AbgKINEr (ORCPT ); Mon, 9 Nov 2020 08:04:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:57432 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730743AbgKINEY (ORCPT ); Mon, 9 Nov 2020 08:04:24 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 19AA120789; Mon, 9 Nov 2020 13:04:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927061; bh=jP88JYj8Z/AdPCNX+iDECNYYOP9MgaPxV5cN5R2kP8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hOXYe98vhoz8ULs4fl9XRqTPTzGeoQl2I2vrqXc8IC+zHZQUkDsbBgNbLK59afbHD kJbYRmndLeyeaFK77PvPpGSmPmIXNuDpRJq5pLCLxS1KIH+RdwpYoUCej45tZaDpj+ L6IOrqUT2F42b2FAmwv4O5w9C7hexBhUMBSGKx7M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Minh Yuan , Michael Ellerman , Jiri Slaby , Greg KH , Linus Torvalds Subject: [PATCH 4.9 080/117] tty: make FONTX ioctl use the tty pointer they were actually passed Date: Mon, 9 Nov 2020 13:55:06 +0100 Message-Id: <20201109125029.484537118@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125025.630721781@linuxfoundation.org> References: <20201109125025.630721781@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Linus Torvalds commit 90bfdeef83f1d6c696039b6a917190dcbbad3220 upstream. Some of the font tty ioctl's always used the current foreground VC for their operations. Don't do that then. This fixes a data race on fg_console. Side note: both Michael Ellerman and Jiri Slaby point out that all these ioctls are deprecated, and should probably have been removed long ago, and everything seems to be using the KDFONTOP ioctl instead. In fact, Michael points out that it looks like busybox's loadfont program seems to have switched over to using KDFONTOP exactly _because_ of this bug (ahem.. 12 years ago ;-). Reported-by: Minh Yuan Acked-by: Michael Ellerman Acked-by: Jiri Slaby Cc: Greg KH Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt_ioctl.c | 32 +++++++++++++++++--------------- 1 file changed, 17 insertions(+), 15 deletions(-) --- a/drivers/tty/vt/vt_ioctl.c +++ b/drivers/tty/vt/vt_ioctl.c @@ -243,7 +243,7 @@ int vt_waitactive(int n) static inline int -do_fontx_ioctl(int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op) +do_fontx_ioctl(struct vc_data *vc, int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op) { struct consolefontdesc cfdarg; int i; @@ -261,15 +261,16 @@ do_fontx_ioctl(int cmd, struct consolefo op->height = cfdarg.charheight; op->charcount = cfdarg.charcount; op->data = cfdarg.chardata; - return con_font_op(vc_cons[fg_console].d, op); - case GIO_FONTX: { + return con_font_op(vc, op); + + case GIO_FONTX: op->op = KD_FONT_OP_GET; op->flags = KD_FONT_FLAG_OLD; op->width = 8; op->height = cfdarg.charheight; op->charcount = cfdarg.charcount; op->data = cfdarg.chardata; - i = con_font_op(vc_cons[fg_console].d, op); + i = con_font_op(vc, op); if (i) return i; cfdarg.charheight = op->height; @@ -277,7 +278,6 @@ do_fontx_ioctl(int cmd, struct consolefo if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc))) return -EFAULT; return 0; - } } return -EINVAL; } @@ -927,7 +927,7 @@ int vt_ioctl(struct tty_struct *tty, op.height = 0; op.charcount = 256; op.data = up; - ret = con_font_op(vc_cons[fg_console].d, &op); + ret = con_font_op(vc, &op); break; } @@ -938,7 +938,7 @@ int vt_ioctl(struct tty_struct *tty, op.height = 32; op.charcount = 256; op.data = up; - ret = con_font_op(vc_cons[fg_console].d, &op); + ret = con_font_op(vc, &op); break; } @@ -955,7 +955,7 @@ int vt_ioctl(struct tty_struct *tty, case PIO_FONTX: case GIO_FONTX: - ret = do_fontx_ioctl(cmd, up, perm, &op); + ret = do_fontx_ioctl(vc, cmd, up, perm, &op); break; case PIO_FONTRESET: @@ -972,11 +972,11 @@ int vt_ioctl(struct tty_struct *tty, { op.op = KD_FONT_OP_SET_DEFAULT; op.data = NULL; - ret = con_font_op(vc_cons[fg_console].d, &op); + ret = con_font_op(vc, &op); if (ret) break; console_lock(); - con_set_default_unimap(vc_cons[fg_console].d); + con_set_default_unimap(vc); console_unlock(); break; } @@ -1103,8 +1103,9 @@ struct compat_consolefontdesc { }; static inline int -compat_fontx_ioctl(int cmd, struct compat_consolefontdesc __user *user_cfd, - int perm, struct console_font_op *op) +compat_fontx_ioctl(struct vc_data *vc, int cmd, + struct compat_consolefontdesc __user *user_cfd, + int perm, struct console_font_op *op) { struct compat_consolefontdesc cfdarg; int i; @@ -1122,7 +1123,8 @@ compat_fontx_ioctl(int cmd, struct compa op->height = cfdarg.charheight; op->charcount = cfdarg.charcount; op->data = compat_ptr(cfdarg.chardata); - return con_font_op(vc_cons[fg_console].d, op); + return con_font_op(vc, op); + case GIO_FONTX: op->op = KD_FONT_OP_GET; op->flags = KD_FONT_FLAG_OLD; @@ -1130,7 +1132,7 @@ compat_fontx_ioctl(int cmd, struct compa op->height = cfdarg.charheight; op->charcount = cfdarg.charcount; op->data = compat_ptr(cfdarg.chardata); - i = con_font_op(vc_cons[fg_console].d, op); + i = con_font_op(vc, op); if (i) return i; cfdarg.charheight = op->height; @@ -1225,7 +1227,7 @@ long vt_compat_ioctl(struct tty_struct * */ case PIO_FONTX: case GIO_FONTX: - ret = compat_fontx_ioctl(cmd, up, perm, &op); + ret = compat_fontx_ioctl(vc, cmd, up, perm, &op); break; case KDFONTOP: